As known, there are a variety of disk drives which use different types of media such as optical disks, optical magnetic disks and flexible magnetic disks. Among them, the hard disk drive (HDD) has become so popular as to be one of the more indispensable storage devices for today's computer systems. Further, not limited to computers, the hard disk drive is widening its range of applications more and more due to its superior characteristics, covering moving picture recording/reproducing apparatus, car navigation systems, removable memories for digital cameras and so on.
The HDD includes a magnetic disk for storing data therein, a head slider which reads/writes data from/to the magnetic disk and an actuator which moves the head slider to a desired position above the magnetic disk. The actuator is driven by a voice coil motor to pivot about a pivot shaft, thereby radially moving the head slider over the rotating magnetic disk.
The head slider includes a slider and a head element portion formed on the surface of the slider. The head element portion includes a write element which converts an electric signal to a magnetic field according to recording data to the magnetic disk and/or a read element which converts a magnetic field from the magnetic disk to an electric signal. The actuator has a resilient suspension and the head slider is fixedly attached to the suspension. The head slider supported by the actuator flies above the rotating magnetic disk at a constant gap therebetween.
The suspension includes gimbals supporting the head slider on the magnetic disk facing side and a load beam supporting the gimbals on the magnetic disk facing side. A wiring structure portion (hereunder called the trace) is formed on the actuator to transmit signals between a preamp IC and an element on the head. The preamp IC is mounted on a FPC (Flexible Printed Circuit) on the actuator in the vicinity of a pivot shaft and the trace is connected to the FPC. The transfer signal of the trace is amplified by the preamp IC.
One known structure of the trace includes a metal layer formed continuously to the gimbals, a plurality of transmission lines formed above the metal layer, and an insulating layer which insulates the transmission lines from the metal layer and also one of the transmission lines from the other transmission lines. Since the trace has the metal layer, handling performance during fabrication can be enhanced. For example, patent document 1 (Japanese Laid-Open Patent No. 2002-251706) discloses a trace with a metal layer in which a hole sequence is formed to overlap a signal line. Forming the hole sequence to overlap the signal line reduces parasitic capacity, thereby increasing the data transfer frequency of the trace.